Apparatus for breaking down material



E. w. SECKENDORFF APPARATUS FOR BREAKING DOWN MATERIAL April 28, 1936.

Filed Aug. 15, 1933 3 Sheets-Sheet l A T'T'Y April 28, 1936- E. w. SECKENDORFF 2,039,264

APPARATUS FOR BREAKING DOWN MATERIAL Filed Aug. 15, 1935 3Sheets-Sheet 2 April 28, 1936.

E. w. SECKENDORFF- Filed Aug. 15, 1 933 APPARATUS FOR BREAKING DOWN MATERIAL s sheets-sheet s [N VEN TO 1-? Ems? W iecken dor' f7;

Patented Apr. 28, 1936 APPARATUS FOR BREAKING DOWN MATERIAL Ernst W. Seckendorff, White Plains, N. -Y. as-

signor to The Jefirey Manufacturing Company,

a corporation of Ohio Application August 15, 1933, Serial No."685,233

. 3 Claims.

The improvements represented by this invention deal principally with an improved construc-.

tion of rotary elements employed in connection with reducing or pulverizing apparatus, wherein material being finely reduced is subjected to the action of rapidly rotating reducing or pulverizing instrumentalities.

In machines of this general type the material to be reduced is fed into a casing in which there are mounted a pair of oppositely rotating overlapping pulverizing devices, each of these devices being provided with lugs operating in relatively close spaced relation with one another and with a grinding surface on the interior of the casing. Suction means are provided for creating air currents through the casing from the feed or charging side thereof to the discharge or outlet side,

whereby the finely reduced or pulverized material is withdrawn from the pulverizing zone and delivered to the desired location. These air currents act upon the material to cause the same to pass first to the periphery of the pulverizing devices and then through the spaces between the lugs thereof and between the devices themselves, thnce through the central portion of the reducing or pulverizing device on'the discharge side of the pulverizing zone. The air currents act upon the material in a direction opposite to the directerior grinding surface of the casing as small as possible in order to assure the maximum reducing action being obtained.

One of the disadvantages of this type of apparatus as heretofore constructed, is the tendency "of the material being reduced to pack between the various surfaces of the pulverizing zone. This packing materially reduces the output of the apparatus, increases the power consumption and lessens the degree of fineness of the particles of the resulting product, thereby substantially decreasing the efiieciency of the machine.

This tendency of the material to pack may be overcome by the present improved construction which enables the material to be maintained at all times in a substantially loose condition. The present invention is based upon the discovery that the desired looseness of the material may be obtained by proper proportioning of the number of pulverizing lugs on the pulverizing devices, and also by properly proportioning the number of such lugs relative to the number of pulverizing instrumentalities provided on the grinding surface of the casing, thereby enabling a reduction in the number of the lugs and in the number of such instrumentalities, with attendant increase in the interstitial spaces therebetween, while maintaining, or even increasing, the degree of fineness of the reduction heretofore obtainable in the previous designs of apparatus when these are operating at their maximum efliciencyi and it has been found that the spaces between the respective pulverizing devices may be increased over those employed in the previous'designs of apparatus, thus further maintainingthe desirable ,degree of looseness in the material being reduced, without detriment to the reducing action thereon. A substantial' economizing of the power consumption is also effected.

Another feature of improvement lies in the provision of the oppositely rotating overlapping pulverizing devices with pulverizing lugs of an ovalor elliptical cross section, the major axis of the cross section in each instance being along the arc of a circle circumscribed by the center point thereof during rotation. This oval or elliptical cross section materially reduces the amount of wear on the lugs during service.

Other incidental improvements in the construction of the present apparatus have been made, which improvements will become apparent as the description proceeds, the novel features and combinations being more particularly pointed out in the appended claims.

tion, the interior of the pulverizing housing and the mounting of the pulverizer, the drive motors and shafts of the rotors being shown in-elevation for purposes of clarity.

Fig. 4 is a transverse section through the housing, taken on the line 4-4 of Fig. 3, looking in the direction of the arrows, the mounting of Fig. 3 being omitted, however, from Fig. 4.

Fig. 5 is a view similar to Fig. 4, but taken on line 5-5 of Fig. 3, looking in the direction of the arrows. i

Fig. 6 is a plan view of the apparatus, showing the casing open for access to the interior thereof, the view illustrating the means; whereby the casing may be opened,*and the operation of the parts for opening the casing.

Fig. '7 is a perspective view of one side of the rotor employed, on the feed or charging side of.

the casing. Z

' material.

Fig. 8 is a perspective view of the opposite side of the rotor of Fig. '7.

Fig. 9 is a perspective view of one side of the rotor employed on the discharge side of the casing the view illustrating the side of the rotor which overlaps the side of the rotor as illustrated in Fig. 7 when the apparatus is assembled.

Fig. 10 is a perspective view of the opposite side of the rotor of Fig. 9.

Fig. 11 is a perspective view of a grinding liner adapted to be positioned in the casing when the parts are assembled, the liner being adjacent the impact lugs of the feed side rotor shown in Fig. 8 and also being adjacent the pulverizing lugs of the rotor of Figs. 9 and 10.

Fig. 12 is a fragmentary sectional view showing the manner of securing the parts of the apparatus in interlocked relation.

Fig. 13 is a sectional view on the line I3-I3 of Fig. 9.

Referring more particularly to the drawings, it will be seen that the invention embraces the unit A which is a pulverizing unit, which receives material to be pulverized, which material is delivered thereto from a storage hopper B and conveyor C, or any equivalent supply mechanism. As installed, the unit A is mounted on a base plate E and a foundation F, which may be of concrete or similar material. Drive instrumentalities, including a motor G which operates gears H, are employed for driving the endless feed conveyor C.

The conveyor C receives the material from the storage hopper B, and discharges the material into the feed hopper I of unit A. This feed hopper I has the throat 2 communicating with the interior of the unit A on the feed side thereof and is mounted on a flange 4 which is shown as being substantially flush with the top of casing 5, in which the pulverizer 6 and fan I are enclosed. The casing 5 is supported on the bed plate or base E, which also supports the motor 8 for driving the fan shaft 9. The inner end of shaft 9 carries the fan side rotor element ID of the pulverizer 6. I

The endless conveyor belt I I enters the hopper I and discharges the material into the feed side of unit A as previously stated. In the path of the discharging material is a permanent magnet I2 which is designed to remove tramp iron from the material. If desired, an electromagnet may be substituted for the permanent magnet I2 which is designed to remove tramp iron from the If desired, such electro-magnet substituted for the permanent magnet may be arranged so as to be energized whenever the feeding mechanism is operated.

A hollow circular closure I3 for the feed side of the casing 4 is provided with an integral platform I4 on which is mounted the motor I5. The shaft I6-of the latter extends inwardly and carries at its inner end the feed side rotor element l'nthe mechanism illustrated in the drawings, when the motor I5 is operated, therotor I1 is rotated relatively to the casing 5 and the closure I3 in a direction opposite to the direction of rotation of the fan side rotor element III, which is driven by the motor 8. The rotor I I iskeyed to the shaft I6 as indicated at I8.

The closure I3 is hinged relative to the housing 6, so that the closure I3, platform I4, motor I5, shaft I6 and rotor Il may be moved axially of the shaft I6 away from the casing 5, and then swung laterally on vertical hinge instrumentalities so that both rotors will be freely accessible tion of set screws 4I.

for inspection, repair, or replacement, while being normally locked in position.

The casing 5 is provided with suitable sockets for the reception of pins 20 which are loosely fitted into the sockets and which are provided with a threaded, transversely extending base which receives the threaded lock bolts 2I which are held between the outstanding pairs of lugs 22 and lock thereagainstv by the provision of the heads 23 on the bolts. A lateral extension 24 is slotted, as indicated at 25, to receive a pin 26 extending upwardly from the base plate E and welded, or otherwise permanently secured, to the base plate. When the lock bolts 2I are loosened, the closure I3 and associated parts may be moved axially of the shaft I6 until at leastv the flange I3a of the closure I3 disengages from its engaging projection 50. of the housing 5, or, if necessary, the axial movement of the closure I3 may be sufficient to bring the pin 26 into engagement with the end of slot 25; in either event the movement being suflicient to enable the rotor I1 to clear the overlapping rotor I0. whereupon the closure I3 and its associated parts may swing arcuately upon pin 26 as a pivot or hinge to take the open position, whereby the interior of the unit A becomes freely accessible. To facilitate this movement, the surface 21 of base plate E is machined perfectly smooth, and the platform I4 is provided with pockets 28,

adapted to receive oily waste for lubricating the surface 21 by drainage of oil through openings 29 in the bottom of the pockets, thereby enabling the platform I4 to slide more easily over the base plate and to prevent the smooth surface of the latter from rusting. Reverse movements enable closure I3 to be brought back into interfitting relation with the .casing 5. For the purpose of properly guiding the return movement of closure I3, a guide bar 30 is suitably secured to the surface 21 of the plate, as by bolts or. equivalent securing members 3|, this bar being engaged by the platform I4 and guiding the platform in its movements relative to the plate.

Shafts 9 and I6, are of course, in perfect alinement in order to provide correct clearance between the parts.

It will be seen that the closure I3, when in closed position, provides a feed chamber 33 for the material dropped from the endless conveyor belt II.

A partition 34 removably mounted in casing 5, is provided with an opening 35 which registers 'with the opening 36 through the central portion of the fan side of rotor element ID. The partition 34 is formed with an annular flange 31 closely engaging a shoulder 36 of the casing 5. A removable cylindrical liner 39 abuts against the flange 31 of the partition 34, thereby holding the latter in place. The removable liner 39 is provided with comparatively wide circumferentially spaced webs 40, projecting into the interior of the liner, and which are arranged in substantially diametrical opposition. These webs 40 extend transversely parallel to the axis of the shafts 9 and I6. For saving material, the liner is recessed behind'alternate ribs. At suitable diametrically opposed points, suitable openings are provided through the casing for the recep- The openings aforesaid are adapted to register with recesses 42 in the liner, these recesses being located behind opposite webs where the metal of the liner is thickened. The recesses 42 are tapered to receive the tapered ends 43 of the set screws 4I. When assembled, the recesses 42 are slightly ofiset relative to the set screws 4|, the set screws thereby acting, when tightened, to aline the recesses 42 with the set screws 4| thereby forcing the liner 39 against the partition 34 in a wholly obvious -manner, thereby clamping the partition tightly in position.

The spaced webs 40 arehardened as well as the inner surface or wall 44 of the liner, so as to provide an efficient breaking and abradlng surface. Circular shoulders or supporting surfaces are provided on the annular flanges 41 and 48 for engagement by radial projecting ribs 400 of the liner 39 to center the liner or to hold the same concentric with the axis of the shafts 9 and I6. The ribs 40a, forming circumferentially distributed points of support, lessen the frictional contact to facilitate removal of the liner when desired, but nevertheless the frictional mounting of the liner, coupled with the clamping action of the set screws 4|, is sufficient to hold the same in clamping position against the partition 34,

and to maintain the opening 49 on its lowermost side in communication with the tramp pocket 59 in the base of casing 5. Further details of the liner structure will be set forth hereinafter.

. material enters the casing through intake opening 52, adjacent which opening the blades 5| are disposed. These blades are of substantial width and in addition to their serving as beaters on the material being pulverized, they act as blower or propeller blades, in conjunction'with fan 1, to draw material through the intake 52 into the pulverizing zone 6 and to impart to the material a preliminary pulverization through the grinding action set up between the blades 5| and the grinding surface of the liner 39. This action will be referred to more fully hereinafter.

When the material to be pulverized falls to the bottom 53 of the chamber 33, it will tend to accumulate therein. If there is any tramp iron, the larger pieces will remain in the bottom 53 of the chamber 33, and may be removed when the closure I3 is opened. Smaller pieces of tramp material that may pass with the other material into engagement with the blades 5| will be ejected through opening 54 into pocket 55 in the bottom of closure l3. To facilitatethis ejection, the edges of the bottom portion of this liner 39 are beveled, as shown at 56. Still other pieces of tramp material that may pass the crusher lugs will escape through the opening 49 into pocket 50' whence it may be withdrawn by removal of the door 51 of the pocket.

Inasmuch as the rotor disc- H is closed, the material to bepulverized must find its way peripherally of the disc between the grinding blades 5| into the pulverizing zone. This passage is facilitated by the coaction of fan I with blades 5|. produce a current of air from the feed side of the disc l'l into the hollow chamber of the feed side rotor "and the fan side rotor 58. Whatever material passes to the peripheral space surrounding the rotor 58 will be further crushed-by impact or" the particles of material against each other and by being thrown by the spaced rotor lugs against the liner 39.

While the air currents through the opening 36 tend to draw the crushed material through the The fan driven by motor 8, is adapted to peripheral space between the lugs and the liner,

and radially to the left of the rotor 58 as viewed in Fig. 3, this tendency is counteracted by; radial fins 59, 59, which produce an effective seal to prevent the passage of coarse material between the back of the rotor 58 and the adjacent wa of the partition 34.

It will be noted that the feed side rotor." is provided with the radially extending ribs or vanes 5| which project beyond the periphery of the rotor I! to adjacent the liner 39, forming the beater lugs 45. The vanes or ribs 5| are adjacent the feed opening 52 which is illustrated as being concentric with shaft I6 and of less diameter than the ribs or vanes 5|. Because of this diameter, blades 5| exert a suction action on the incoming material and impel the material against the liner 39 for preliminary pulverization through impact against the liner, through action of the lugs 45 and the action of the particles on each other, this initial pulverization occurring in space 6|.

Extending in the direction of the axis of rotation of the rotor H are a plurality of lugs 45, which are shaped as clearly indicated in the drawings, being preferably substantially elliptical in cross section, this shape being found to present a maximum surface to the material for pulverization thereof while being subjected to the minimum of wear. These lugs are spaced apart in such a manner that they will act as a screen to prevent passage therebetweemat operative speeds of the rotor, of any relatively coarse particles.

The fan side rotor 58 carries the pulverizing lugs 69 which overlap the lugs 46 of the feed side rotor. These lugs are of similar configuration to the lugs 46. It will be noted that the major axis of the lugs 46 and 60, in each instance, extendsbetween the lugs and the liner 39, the material of course being substantially finer in this space than in the space 6| around the lugs 45. The centrifugal force exerted by the rotors rejects the coarser particles from between the space 62 between the rotors, only those particles in a sufficiently fine state of subdivision to be unaffected by the centrifugal force being drawn by the action of fan 1 through space 62 between the lugs 46 and 60.

Experience has shown that the number of lugs 60 on the fan side rotorw should be such that not more than three lugs 46 on the feed side rotor should be in opposition with three lugs 60 on the fan side rotor at any given moment of time. If this ratio is increased, experience has shown that there isa tendency of the material being pul- I verized to pack around the rotors, and preferably the ratio should be less than one to three in order to assure a free flow of material continuously. This packing of the material is objectionablein that it increases power consumption, decreases the output of the apparatus, and reduces the apparatus, and reducing the amount of wear on the parts. As illustrated, rotors l1 and 58 rotate at high speeds in opposite directions.

In addition to the increased wearing qualities imparted to the rotor lugs by virtue of the curved surfaces thereof, the shape of the lugs increases the eiliciency of the apparatus by virtue of opposing lugs exerting a Venturi action upon the material being pulverized, as the opposing lugs approach each other. This Venturi action is produccd by the curving sides of the lugs acting as a funnel, and thus facilitates the drawing of the fine particles into the space 62.

Considering further the construction of the fan side rotor 58, it will be observed that the central portion of the rotor is extended into the limits of the opening 35 of the auxiliary partition 34, thus forming a rim around the opening 38 in the central portion of the fan side rotor. This rim 63 is beveled at such an angle that there will be no tendency of the material being pulverized to collect around the periphery of the opening. This angle in practice as found is substantially 45, where coal is the material being pulverized. The beveled rim 63 also directs the material into the central portion of the fan I.

The action of the fan I is increased by the shape and disposition of the webs 84, reinforcing the rim 63. These webs 64 may be substantially oval in cross section, being shaped as propeller blades and act in conjunction with the fan 1 to pull material from the pulverizing zone. This arrangement also results in a substantial saving of power.

The lugs 46 and 6,0 are so arranged that at a given instant there will be not more than a total of three lugs on the feed side rotor in direct opposition with three corresponding lugs on the fan side rotor, the point of opposition of the lugson the two rotors occurring every 0.001 second.

Where the outside diameter of the fan side rotor 58 is ten inches, for example, and the outside diameter of the feed side rotor I1 is seven and one-half inches, it has been found experimentally that maximum efliciency with respect to lowered power consumption and increased output and fineness of grinding, isobtained by providing six of the lugs on the fan side rotor 58, nine of the lugs 46 on the feed side rotor l1 and three beater lugs 45. With such arrangement, see Fig. 4, it will be seen that just three of the lugs 46 are in opposition at any given instant with three corresponding lugs 68 on the fan side rotor 58. The intermediate lugs 46 pick up the material between the rotors and push it ahead until the point of opposition is reached, when the grinding ac- 'tion takes place; and as previously stated, the

point of opposition of the -lugs on 'the two rotors occurs every 0.001 second. The lugs 45 on the feed side rotor rotate with sufficient rapidity to act as a screen to prevent the coarse particles of material from passing through the spaces between the lugs. I

Referring in more detail to the liner 39, it has already been said that the liner is provided with a plurality of grinding ribs 48, which project inwardly of the liner, and extend parallel to the rotor axes. Of these ribs, alternate ones only extend completely across the liner, as will be apparent from the drawings, the short ribs extending only across the zone of action of the fan side rotor. This means that an increasingly fine subdivision of the particles is carried out on the fan side rotor. However, not more than two of lugs 60 which two lugs are diametrically opposed are in'opposition at any given instant with corresponding diametrically opposed liner ribs; It will also be seen that as the lugs 60 pass the ribs, the clearance between the lugs and liner is approximately double the clearance between the lugs and the ribs. This increased clearance between the ribs enables the material to be pulverized to be swept freely along by the action of the lugs and air currents, and prevents any tendency of the material to pack between the respec tive surfaces. Experience has shown, also, that a greater number than two coincidences will tend to obstruct the passage of air irrespective of the size of the rotor,

on the feed side rotor 11, only one of the lugs 45 is in opposition, at any given time instant, with a rib on the liner. 4

It will'be noted from the drawings that the feed side rotor I1 is mounted on the shaft [6 through a hub 65 adjustably keyed to the shaft through a set screw 66, and the fan side rotor 58 likewise is adjustably keyed to the shaft 9 by a set screw 61 and hub 68. Fan 1 is secured on the shaft 9 between the end of the rotor hub 68 and the motor 8.

The following data is given as illustrative of the dimensions and operative factors of a typical operative device constructed in accordance with this invention, it being understood that these are given merely by way of an illustrative example,

and may be varied in any manner as may be necessary to fulfill the requirements of a particular installation, the data being based upon coal as the material being pulverized.

Diameter of fan side rotor inches 10 Diameter of feed side rotor inclusive of beater lugs inches 10 Diameter of feed side rotor exclusive of beater lugs inches 7 Diameter of liner between ribs do 11 Diameter of liner intermediate adjacent ribs inches 11% Diameter of auxiliary partition on fan side of easing inches 12 Outside diameter of central rim on fan side rotor inches 6% Inside diameter of central rim on fan side rotor inches 6 Diameter of rotor bushings do 2 Diameter of rotor shafts do 1 No. lugs on fan side rotor 6 Length of lugs inches 2% Major diameterof lugs -do 1% No. lugs on feed side rotor 9 Major diameter of lugs inches 1 No. beater lugs on feed side rotor 3 Length of beater lugs on feed side rotor inches l A; -Width of beater lugs on feed side rotor inches 1 No. pulverizing ribs on liner 8 Distance between lugs on fan side rotor and lugs on feed side rotor inch Distance between lugs on fan side rotor and ribs on liner inch Distance between beater lugs on feed side rotor and ribs on liner inch Time interval for frequency of lugs on both rotors to be in opposing positions second 0.001

The number of lugs per second" is obtained by multiplying the R. P. M. of the motor by the number of lugs and dividing by sixty seconds.

The time interval is the fraction of a second between lugs, or the time required for one lug to move the distance of its spacing. This value is obtained by dividing one second by the number of lugs per second.

From the above data, the details of construction of the rotors for any given installation may be determined. When pulverizing coal experience has shown that irrespective of the size of the rotors, best results are obtained by maintaining substantially constant at 0.001 second the time interval for --the frequency of the lugs on both rotors to be in opposing positions, and the number of lugs on the rotors will be dependent upon the speed of rotation of the rotors. Taking the above angular velocities as the basis for determining the number of lugs on the feed and fan side rotors, the following formulae may be used:

For the feed side rotor,

For the fan side rotor,

Where Z1=number of lugs on feed side rotor Zz=number oilugs on fan side rotor Ni=number of revolutions of feed side rotor Nz=number of revolutions 'of fan side rotor Experience has indicated that good results will be uniformly obtained by maintaining the clearance betweenthe feed and fan side rotors and between rotors and liner ribs at approximately one-half inch, independent 'of the size of the rotor.

' The numerical quantities in. the above formula are obtained by adding together the M. of the two motors as given in the speciilc"-illu strationand multiplying this total R. P. M. by the number of lugs on rotors of the above illustration. The above specifically described constructionmay be taken as a standard or'basis from which to work.

The construction as detailed above is designed, when grinding coal, to give a product substantially 80% or which will be not greater than 200 riphery of the opening, and reinforcing webs for mesh. The fineness of pulverizatlon may be adjusted, if desired, by varying the distance between the rotors by adjusting the set screws 66 and 0,1. The base plate E is provided with a plurality of channel members, indicated at 6 9, which are adapted to be embedded in a concrete. or equivalent, foundation when the apparatus is mounted for service. The top surface of the plate I! is machined very smooth to facilitate the movement of closure i3, and in order toreadily level the unit when it is installed on its supporting foundation structure, grout holes 1| are provided in the plate E, through which holes any necessary concrete may be introduced for leveling the machine.

It will be further noted that the fan compartment is provided with ports 10 for introduction of supplemental air to the fan I.

Obviously those skilled in the art may make various changes in the details and arrangement of parts without departing from the spirit and scope of the invention as defined by the claims hereto appended and I wish therefore not to be '.restricted to the precise construction herein disclosed.

Having thus described and shown an embodiment of my invention, what I desire to secure by Letters Patent of the United States is:

1. Apparatus for breaking down materials comprising the combination with a casing, of an auxiliary partition enclosed within the casing, the partition having an opening therethrough for passage of material being pulverized, a pulverizing rotor adjacent the partition on one side thereof comprising a disc having a central opening therethrough for passage of material and a rim around the opening extending into the partition opening, a suction fan on the opposite side of the partition and propeller blades mounted on the rotor across the opening therethrough to supplement the action of the fan to feed the material through the said opening.

2. An article of manufacture comprising a rotor for breaking down materials, comprising a disc having pulverizing lugs extending from one side thereof parallel to the axis or the disc, the said lugs being outwardly tapering and of substantially elliptical cross section, the major axis of each lug being disposed substantially along the arc of a circle circumscribed by the center point thereof during rotation, the said disc being provided with an opening therethrough, webs of propeller blade shape extending across the opening for feeding pulverized material throughthe said opening and away from said lugs, a rim around the opening extending from the surface of the disc opposite to the surface from which the said lugs project, the rim being bevelled at an angle preventing collection of pulverized material around the periphery of the opening.

3. An' article of'manufacture, a rotor for breakingdown materials, comprising a'disc having pulverizing lugs extending from one face thereof, the rotor body being, provided with an opening therethrou'gh, throughmhich opening pulverized material. is adapted to feed, a rim extending around the opening and extending,

from the opposite face of the rotor body, the said rim being beveled at an angle preventing collection of pulverized material around the pe- 

